From Ross-Tech Wiki

2.2 What's the difference between the Shareware version and the fully registered version?
All of our Current Interfaces have Activation built-in, so VAG-COM will always be Fully Registered/Activated. If you have an older Interface without built-in Activation, or have purchased an Interface somewhere other than Ross-Tech, VAG-COM will operate in Shareware mode until it is Activated. The differences between Shareware and fully registered/activated versions are listed near the bottom of each function page in the Online Demo / Manual and in the VAG-COM Function Chart.